Multi-zone electrochromic device

ABSTRACT

In one aspect of the present invention is a substrate comprising multiple, independently controllable electrochromic zones, wherein each of the electrochromic zones share a common, continuous bus bar. In one embodiment, of the electrochromic zones are not completely isolated from each other. In another embodiment, each of the electrochromic zones have the same surface area. In another embodiment, each of the electrochromic zones have a different surface area.

CROSS REFERENCE OF RELATED APPLICATIONS

The present application is a continuation-in-part of U.S. patentapplication Ser. No. 13/407,106, filed on Feb. 28, 2012, the disclosureof which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

Electrochromic devices include electrochromic materials that are knownto change their optical properties, such as coloration, in response tothe application of an electrical potential, thereby making the devicemore or less transparent or more or less reflective. Typical prior artelectrochromic devices include a counter electrode layer, anelectrochromic material layer which is deposited substantially parallelto the counter electrode layer, and an ionically conductive layerseparating the counter electrode layer from the electrochromic layerrespectively. In addition, two transparent conductive layersrespectively are substantially parallel to and in contact with thecounter electrode layer and the electrochromic layer. Materials formaking the counter electrode layer, the electrochromic material layer,the ionically conductive layer and the conductive layers are known anddescribed, for example, in U.S. Patent Application No. 2008/0169185,incorporated by reference herein, and desirably are substantiallytransparent oxides or nitrides. When an electric potential is appliedacross the layered structure of the electrochromic device, such as byconnecting the respective conductive layers to a low voltage electricalsource, ions, such as Li+ ions stored in the counter electrode layer,flow from the counter electrode layer, through the ion conductor layerand to the electrochromic layer. In addition, electrons flow from thecounter electrode layer, around an external circuit including a lowvoltage electrical source, to the electrochromic layer so as to maintaincharge neutrality in the counter electrode layer and the electrochromiclayer. The transfer of ions and electrons to the electrochromic layercauses the optical characteristics of the electrochromic layer, andoptionally the counter electrode layer in a complementary EC device, tochange, thereby changing the coloration and, thus, the transparency ofthe electrochromic device.

FIGS. 1A and 1B illustrate plan and cross-sectional views, respectively,of a typical prior art electrochromic device 20. The device 20 includesisolated transparent conductive layer regions 26A and 26B that have beenformed on a substrate 34, such as glass. In addition, the device 20includes a counter electrode layer 28, an ion conductive layer 32, anelectrochromic layer 30 and a transparent conductive layer 24, whichhave been deposited in sequence over the conductive layer regions 26. Itis to be understood that the relative positions of the electrochromicand counter electrode layers of the device 20 may be interchanged.Further, the device 20 includes a bus bar 40 which is in contact onlywith the conductive layer region 26A, and a bus bar 42 which may beformed on the conductive layer region 26B and is in contact with theconductive layer 24. The conductive layer region 26A is physicallyisolated from the conductive layer region 26B and the bus bar 42, andthe conductive layer 24 is physically isolated from the bus bar 40.Although an electrochromic device may have a variety of shapes, such asincluding curved sides, the illustrative, exemplary device 20 is arectangular device with the bus bars 40 and 42 extending parallel toeach other, adjacent to respective opposing sides 25, 27 of the device20, and separated from each other by a distance W. Further, the bus bars40 and 42 are connected by wires to positive and negative terminals,respectively, of a low voltage electrical source 22 (the wires and thesource 22 together constituting an “external circuit”).

Referring to FIGS. 1A and 1B, when the source 22 is operated to apply anelectrical potential across the bus bars 40, 42, electrons, and thus acurrent, flows from the bus bar 42, across the transparent conductivelayer 24 and into the electrochromic layer 30. In addition, if the ionconductive layer 32 is an imperfect electronic insulator as is the casein many thin film EC devices, a small current, commonly referred to as aleakage current, flows from the bus bar 42, through the conductive layer24 and the electrochromic layer 30, and into the ion conductive layer32. Further, ions flow from the counter electrode layer 28, through theion conductive layer 32, and to the electrochromic layer 30, and acharge balance is maintained by electrons being extracted from thecounter electrode layer 28, and then being inserted into theelectrochromic layer 30 via the external circuit. As the current flowsaway from the bus bar 42 across the conductive layer 24 and towards thebus bar 40, voltage is dropped by virtue of the finite sheet resistanceof the conductive layer 24, which is typically about 10-20 Ohms/square.In addition, current flowing across the conductive layer 24 isincrementally reduced, as current is drawn through the combination ofthe layers 30, 32 and 28 (“stack”) to produce the electrochromiccoloration in the device 20.

Consequently, it is believed that if the device 20 is considered to beformed from successive adjacent segments arranged between the bus bars40, 42 and extending between the transparent conductor layer 24 and theconductive layer region 26B, the amount of current flowing through thestack at the segment of the conductive layer 24 closest to the bus bar40 will be close to zero, as the majority of the current will havepassed down through the stack. Assuming that the sheet resistance of thetransparent conductive layer 24 is substantially uniform between the busbars 40 and 42, the voltage drop across the transparent conductive layer24 extending between the bus bars 40, 42, will be proportional to thecurrent flowing through each successive segment of the device 20. Thus,the rate of voltage drop in the transparent conductive layer withrespect to distance away from the bus bar 42 will be at a maximumclosest to the bus bar 42 and practically zero close to the bus bar 40.A substantially mirrored image of the current flow occurs with respectto the flow of current from the bus bar 40 across the conductive layerregion 26A and toward the bus bar 42, in that the current flow acrossthe device 20 in the conductive layer region 26A increases from the busbar 40 to the bus bar 42 as a result of contributions from successivesegments of the device 20. The difference between the voltage profilesfor the conductive layer 24 and the conductive layer region 26A, acrossthe width of the device between the bus bars 40, 42, is the potentialdifference between the conductive layer 24 and the conductive layerregion 26A across the width of the electrochromic device extendingbetween the bus bars 40, 42.

The potential difference determines the maximum rate of current flowthrough each segment from the counter electrode layer 28 to theelectrochromic layer 30 causing the device 20 to transform to a coloredstate and, thus, causing coloring of the device 20. Current will flow ata rate proportional to the potential difference across the segments ofthe device, provided there is a ready supply of charge, in the form oflithium ions and electrons, to satisfy the requirements. The net resultis that a non-uniform coloration is initially produced, with the regionsclosest to the bus-bars, where the potential difference between thetransparent conductors is largest, coloring faster than the region inthe middle of the device. In an ideal device, which would not have anyleakage current, this non-uniformity will even out as the supply ofavailable charge in the counter electrode layer is exhausted, firstclosest to the bus-bars, and then in the center of the device, as theelectrochromic device attains a fully colored state, thereby yieldinguniform coloration across the entire area of the device.

After a voltage is initially applied across the bus bars 40, 42 of theelectrochromic device 20, the current flowing through the device 20 willdrop towards zero, and thus the voltage drops across each of thetransparent conductive layers will also approach zero. Whether thevoltage between the conductive layer 24 and the conductive layer region26A, across the width of the electrochromic device 20 extending betweenthe bus bars 40, 42, will become equal or substantially equal to aconstant, such as about the applied voltage, in the fully colored state,thereby ultimately yielding a relatively uniform coloration in theelectrochromic device 20, however, depends in part upon the width of theconductive layer 24 and the conductive layer region 26A of theelectrochromic device 20 extending between the bus bars 40, 42 acrosswhich the current flows and the magnitude of the leakage current throughthe device.

In large sized electrochromic devices having a construction similar tothat of the device 20, where the current flows a relatively largedistance, such as in excess of about 40 inches, across the conductivelayers of the electrochromic device between the opposing bus bars,non-uniform coloration of the device may persist even at fullcoloration, because a large and non-uniform voltage drop occurs throughthe stack across the width of the conductive layers extending from theopposing bus bars. This non-uniform voltage drop is caused by theeffects of leakage current through the device, which is typicallypresent in electrochromic devices because of the thin-film constructionof the layers of the stack. Leakage current flows through the stack,such that a potential difference variation is created across the widthof the electrochromic device extending between the bus bars. If theleakage current is significantly large, the potential differencevariation becomes sufficiently large to cause a non-uniform colorationin the electrochromic device that may be visible to the naked eye. Thenon-uniform coloration in the electrochromic device typically results ina lighter area near a region midway between the opposing bus bars(“middle region”), than at regions of the electrochromic device near thebus bars. In other words, the middle region of the electrochromic devicedoes not experience the same color change, or the same amount ofdarkening or consistency of darkening, as those regions closer to thebus bars at the sides of the electrochromic device.

It is has been observed that when electrochromic devices constructedsimilar to the device 20 are operated at normal operating voltages, suchas between around 2.5V and 4.0V, the leakage current is on the order of50-500 mA/m², such that non-uniform coloration across the electrochromicdevice may become visible to a naked eye when the distance between theopposing bus bars is at least about 30 inches. For typical leakagecurrent levels, color non-uniformity is not readily apparent to thenaked eye when the electrochromic device is in the fully colored stateand has bus-bar separations less than about 30 inches.

Referring to FIG. 1A, it is highly desirable to position the bus bars40, 42 very close to the sides 25, 27 of the device 20 to maximize theregion of the device 20, which is between the bus bars 40, 42 and, thus,in which coloration can be controlled. Also, by positioning the bus barsnear the sides of the device 20, the bus bars, which typically have athickness of not more than about 0.25 inches, are not visible or areminimally visible, such that the device is aesthetically pleasing wheninstalled in a typical window frame. Large sized electrochromic devices,in which the distance between the bus bars, which typically are atopposing sides of the device, is in excess of about 40 inches, aredesirable for many applications, such as a window of an office buildingor a glass windshield of a car. Thus, in the operation of such largesized electrochromic devices, non-uniform coloration may occur due tothe effects of leakage currents, as discussed above, which is notdesirable.

Also, it has been observed that, in large sized electrochromic devicessimilar to the device 20, the regions of the device adjacent to theopposing bus bars change color or darken more quickly than at a middleregion between the bus bars. Further, it has been observed that thesesame large sized electrochromic devices may change transmission state(or color) more slowly than electrochromic devices having smallerdistances between opposing bus bars. This phenomenon is largely due tothe current draw in the larger device being larger, and thereforeleading to a larger voltage drop in the transparent conductor layers,thereby reducing the net potential applied to the stack relative to anelectrochromic device having a smaller width between opposing bus bars.Also, the slower change in coloration is based, in part, on theapplication of a voltage to the electrochromic device which is below amaximum level, such as 3V, to avoid overdriving of the electrochromicdevice at the portions near the bus bars, which may cause damage to thelayers of the stack.

For example, for a prior art electrochromic device similar to the device20 having opposing bus bars separated by about six inches, the typicaltime for the device to change from a full transmission state (fullyclear) to a colored state where only five percent of light istransmitted through the device is about 100 seconds, whereas for anelectrochromic device similar to the device 20 having bus bars separatedby about thirty inches the typical time for obtaining the samecoloration change may be about as much as 400 seconds.

US Publication No. 2011/0260961 discloses a three-bus electrochromicdevice, wherein the two zones formed are not independently controllable.

US Publication No. 2009/0323160 discloses a zoned electrochromic devicecomprising an area between two adjacent dynamic electrochromic zoneswhich electrically isolates the two adjacent dynamic electrochromiczones. In other words, this publication discloses zones which arecompletely isolated.

SUMMARY OF THE INVENTION

In one aspect of the present invention is a substrate comprisingmultiple, independently controllable electrochromic zones, wherein eachof the electrochromic zones share a common, continuous bus bar. In oneembodiment, of the electrochromic zones are not completely isolated fromeach other. In another embodiment, each of the electrochromic zones havethe same surface area. In another embodiment, each of the electrochromiczones have a different surface area. In some embodiments, the substrateis a laminate. In some embodiments, the electrochromic zones comprise atleast one thin film comprising a mixed tungsten-nickel oxide.

In another embodiment, the substrate comprises three bus bars. Inanother embodiment, the three bus bars are spaced such that a interiorbus bar is sandwiched between a first end bus bar and a second end busbar. In another embodiment, a first electrochromic zone is defined bythe space between the interior bus bar and the first end bus bar and asecond electrochromic zone is defined by the space between the interiorbus bar and the second end bus bar. In another embodiment, theelectrochromic zones are formed from a single electrochromic coating onthe substrate. In another embodiment, the three bus bars aresubstantially parallel to each other. In another embodiment, the threebus bars run substantially the length of the substrate and each of thethree bus bars are approximately the same size. In some embodiments, thesubstrate is a laminate. In some embodiments, the electrochromic zonescomprise at least one thin film comprising a mixed tungsten-nickeloxide.

In another embodiment, the electrochromic zones are formed from a singleelectrochromic coating on the substrate, wherein the singleelectrochromic coating is cut to form individual electrochromic zones.In another embodiment, the substrate comprises a first bus bar and asecond bus bar, wherein the first bus bar runs continuously over eachelectrochromic zone. In another embodiment, the second bus bar is formedfrom a single bus bar and cut to form individual bus bar segments,wherein each bus bar segment corresponds to an electrochromic zone.

In yet another embodiment, both bus bars are cut into multiple segments,but in different places, to create multiple electrochromic zones. Thisis believed to be especially useful in creating a 3-zone device bycutting each bus bar into two segments. But this is just not limited to3-zone devices (e.g. can be applied to two zone devices or deviceshaving more than three zones). In some embodiments, the electrochromiczones comprise at least one thin film comprising a mixed tungsten-nickeloxide. In some embodiments, the electrochromic zones are deposited on asubstrate which a laminate.

In another embodiment, the substrate is selected from the groupconsisting of glass, plastic, and a laminate of two of the same ordifferent materials. In another embodiment, the substrate is a windowpane or window assembly. In another embodiment, the substrate is a partof an insulated glass unit.

In another embodiment, each of the multiple electrochromic zonescomprise: a first electrode comprising one of an electrochromic layer ora counter electrode layer, a second electrode comprising other of theelectrochromic layer or the counter electrode layer, an ion-conductorlayer for conducting ions between the first and second electrodes, afirst conductive layer, and a second conductive layer, the first andsecond electrodes and the ion-conductor layer being sandwiched betweenthe first and second conductive layers.

In another aspect of the present invention is a method of forming asubstrate having multiple electrochromic zones comprising: (1)depositing an electrochromic coating on the substrate, and (2)depositing multiple bus bars on the electrochromic coating so as to formmultiple electrochromic zones from the electrochromic coating, whereinthe formed multiple electrochromic zones share at least one commoncontinuous bus bar. In one embodiment, the method comprises depositingat least three bus bars such that the spacing of the at least three busbars forms at least two electrochromic zones. In another embodiment, theelectrochromic coating is cut to form two electrochromic zones.

In another aspect of the present invention, is a method of controlling amulti-zone electrochromic device.

In another aspect of the present invention, is a method of installing amulti-zone electrochromic device, or an IGU comprising a multi-zoneelectrochromic device, in a vehicle or building.

In one aspect of the present invention is a substrate comprisingmultiple independently controllable electrochromic zones and at leasttwo bus bars, wherein each bus bar is segmented, and wherein at leasttwo adjacent electrochromic zones share a continuous portion of at leastone of the bus bars. In some embodiments, the substrate is a laminate.In some embodiments, the electrochromic zones comprise at least one thinfilm comprising a mixed tungsten-nickel oxide.

In another aspect of the present invention is substrate comprising atleast three independently controllable electrochromic zones, theelectrochromic zones being arranged sequentially, and wherein no morethan any two adjacent electrochromic zones share a continuous portion ofat least one of the bus bars. In some embodiments, the substratecomprises three independently controllable electrochromic zones. In someembodiments, adjacent first and second zones share a common portion of afirst segmented bus bar and wherein adjacent second and third zonesshare a common portion of a second segmented bus bar. In someembodiments, each of the electrochromic zones have different surfaceareas. In some embodiments, each of the electrochromic zones are notcompletely isolated from each other. In some embodiments, theelectrochromic zones are formed from a single electrochromic coating onthe substrate. In some embodiments, the first and second segmented busbars are substantially parallel to each other. In some embodiments,collective portions of the first segmented bus bar and collectiveportions of the second segmented bus bar run substantially the length ofthe substrate. In some embodiments, the substrate is a laminate. In someembodiments, the electrochromic zones comprise at least one thin filmcomprising a mixed tungsten-nickel oxide.

In some embodiments, the substrate comprises four independentlycontrollable electrochromic zones. In some embodiments, adjacent firstand second zones share a common portion of a first segmented bus bar andadjacent third and fourth zones share a common portion of a secondsegmented bus bar. In some embodiments, the substrate is a laminate. Insome embodiments, the electrochromic zones comprise at least one thinfilm comprising a mixed tungsten-nickel oxide.

In another aspect of the present invention is a method of forming asubstrate having at least two independently controllable electrochromiczones comprising: (1) depositing an electrochromic coating on asubstrate; and (2) depositing two bus bars on the electrochromiccoating, wherein at least one of the bus bars are discontinuous, eachhaving at least two portions. In some embodiments, the substrate is alaminate. In some embodiments, the substrate comprises threeelectrochromic zones. In some embodiments, first and second zones sharea common portion of a first segmented bus bar and wherein adjacentsecond and third zones share a common portion of a second segmented busbar. In some embodiments, each of the electrochromic zones havedifferent surface areas. In some embodiments, each of the electrochromiczones are not completely isolated from each other. In some embodiments,the electrochromic zones are formed from a single electrochromic coatingon the substrate. In some embodiments, the substrate comprises fourelectrochromic zones. In some embodiments, the electrochromic zonescomprise at least one thin film comprising a mixed tungsten-nickeloxide.

In another aspect of the present invention is an electrochromic devicecomprising a substrate wherein the substrate comprises multipleindependently controllable electrochromic zones and at least two busbars, wherein each bus bar is segmented, and wherein at least twoadjacent electrochromic zones share a continuous portion of at least oneof the bus bars. In some embodiments, the electrochromic zones compriseat least one thin film comprising a mixed tungsten-nickel oxide.

In another aspect of the present invention is an electrochromic devicecomprising a substrate wherein the substrate comprises at least threeindependently controllable electrochromic zones, the electrochromiczones being arranged sequentially, and wherein no more than any twoadjacent electrochromic zones share a continuous portion of at least oneof the bus bars. In some embodiments, the electrochromic zones compriseat least one thin film comprising a mixed tungsten-nickel oxide.

In another aspect of the present invention is an insulated glazing unitcomprising an electrochromic device wherein the electrochromic devicescomprises a substrate wherein the substrate comprises multipleindependently controllable electrochromic zones and at least two busbars, wherein each bus bar is segmented, and wherein at least twoadjacent electrochromic zones share a continuous portion of at least oneof the bus bars. In some embodiments, the electrochromic zones compriseat least one thin film comprising a mixed tungsten-nickel oxide.

In another aspect of the present invention is an insulated glazing unitcomprising an electrochromic device wherein the electrochromic devicecomprises a substrate wherein the substrate comprises at least threeindependently controllable electrochromic zones, the electrochromiczones being arranged sequentially, and wherein no more than any twoadjacent electrochromic zones share a continuous portion of at least oneof the bus bars. In some embodiments, the electrochromic zones compriseat least one thin film comprising a mixed tungsten-nickel oxide.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a top plan view of a prior art electrochromic device.

FIG. 1B is a view of the electrochromic device of FIG. 1A atcross-sectional line 1B-1B.

FIG. 2 is a cross-sectional view of a multi-zone electrochromic device.

FIG. 3A is a top plan view of a multi-zone electrochromic device.

FIG. 3B is a cross-sectional view of a multi-zone electrochromic device.

FIG. 4A depicts an electrochromic device having two zones and threewires.

FIG. 4B depicts an electrochromic device having three zones and fourwires.

FIG. 5 depicts a three zone electrochromic device, and associatedwiring, where one of the zones has a non-rectangular shape.

FIG. 6 depicts a two zone electrochromic device, and associated wiring,where the electrochromic device comprises a segmented bus bar.

FIG. 7 depicts a 2-pane, 3-busbar electrochromic device, showing thethree electrical connections with applied voltages and currents.

FIG. 8 depicts a 3-pane, 4-busbar electrochromic device, showing thefour electrical connections with applied voltages and currents.

FIG. 9 depicts a 2-pane, isolation-zoned electrochromic device, showingthe three electrical connections with applied voltages and currents.

FIG. 10 depicts a 3-pane, isolation-zoned electrochromic device, showingthe four electrical connections with applied voltages and currents.

FIG. 11 provides a more detailed illustration of the 3-pane,isolation-zoned device, showing bus bar segments and laser isolatingprocesses.

DETAILED DESCRIPTION

In one aspect of the present invention is a substrate comprisingmultiple, independently controllable electrochromic zones, wherein eachof the electrochromic zones share a common, continuous bus bar. In oneembodiment, each of the electrochromic zones are not completely isolatedfrom each other. In some embodiments, each of the electrochromic zonesmay have the same or different sizes and/or surface areas. In otherembodiments, each of the electrochromic zones may have the same ordifferent shapes (including curved or arcuate shapes).

Generally, the multi-zone EC devices of the present invention fall intotwo categories: (1) those comprising two bus bars at the opposing sidesor edges of an EC device and additional bus bars positioned in aninterior spaced between the opposing side or edge bus bars; and (2)those where electrochromic zones are formed from a single electrochromiccoating on a substrate, wherein the single electrochromic coating is cutto form individual electrochromic zones. Each of these types ofmulti-zone EC devices, and their respective processes of fabrication,are discussed herein.

It is believed that multi-zone electrochromic devices according to thepresent invention provide many advantages over conventional dynamicIGUs, such as permitting optimized harvesting of natural daylightthrough one or more dynamic zones, while being able to maximizesolar-control advantages in the other dynamic zones of the window.Different dynamic zones can be created at any arbitrary distance fromthe edge of a window in order to satisfy diverse design goals andrequirements.

In one aspect of the present invention is a multi-zone electrochromicdevice where, in addition to the bus bars disposed at the opposing sidesof an EC device, additional bus bars are positioned in an interior spacebetween the opposing side bus bars. In one embodiment, an interior busbar is positioned between a first end opposing bus bar and a second endopposing bus bar. Of course, the present invention is not limited toembodiments where multi-zone EC devices comprise three bus bars andhence two zones. Multi-zone EC devices comprising four or more bus bars(having three or more zones, respectively) are equally contemplated.

For example, referring to FIG. 2, a multi-zone electrochromic device 200includes two independently operable and controllable zones, namely 200Aand 200B (or electrochromic device zones). An exemplary multi-zone ECdevice 200 may include a central bus bar 242 and bus bars 240A and 240Bat the opposing sides or edges of the respective zones (“outside busbars” or “first and second opposing end bus bars”). The interior bus bar242 is common to both of zones 200A and 200B of the multi-zone EC device200. Accordingly, a first electrochromic zone 200A is defined by thespace between the interior bus bar 242 and the first end bus bar 240Aand a second electrochromic zone 200B is defined by the space betweenthe interior bus bar 242 and the second end bus bar 240B.

In this particular embodiment of FIG. 2, the interior bus bar ispositioned at a central location relative to the first and second endopposing bus bars. However, the interior bus bar may be present at anyposition between the first and second end opposing bus bars. The busbars 242 and 240A and 240B may be separated by the same or differentdistances. In some embodiments, the bus bar 242 is in a central regionof the device and is positioned equidistant from each of bus bars 240Aand 240B. In other embodiments, the bus bar 242 is positioned betweenthe bus bars 240A and 240B, but the distance between 242 and 240A isdifferent than the distance between 242 and 240B.

In embodiments having more than two zones, the additional interior busbars may be positioned at any location between the first and second endopposing bus bars. For example, the additional interior bus barscomprising a device having more than two zones may be placed atequidistant intervals between the first and second end opposing busbars. It is believed that this may result in a device having multiplezones, where each zone has about the same surface area. Alternatively,the additional interior bus bars comprising a device having more thantwo zones may be placed at different distances between the first andsecond opposing end bus bars, resulting in zones having differentsurface areas.

The multi-zone device is fabricated on a single substrate (e.g. glass orplastic). In some embodiments, the multi-zone electrochromic device isproduced from a single continuous EC device (i.e. a single continuousstack of thin films deposited on a glass substrate). In otherembodiments, two EC devices are independently deposited on a glasssubstrate, which each individually deposited EC device has a single busbar at a side or edge and whereby an interior bus bar is deposited andshared between both devices. For example, a first device 20 is disposedadjacent to and in mirror image to a second device 20, such that the busbars 42 of the respective first and second devices 20 contact eachother. The compositional layers comprising an EC device and their methodof formation or deposition are disclosed in U.S. Pat. Nos. 8,004,744,7,830,585, 7,593,154, 7,372,610, the disclosures of each are herebyincorporated by reference herein in their entirety. For example,techniques for forming the layers of an electrochromic zone or anelectrochromic device in a well-known manner generally comprise physicalvapor deposition, sputtering, pyrolytic-coating techniques, wet-chemicaltechniques, such as a sol gel process, spin-coating techniques, andvacuum-coating techniques.

In some embodiments, the glass substrate is coated with a bottomtransparent conductor. This conductor is then cut with a P1 process toisolate different regions of the coatings, as shown in FIGS. 3A and 3B.Next, the electrochromic films are coated over the top, followed by theupper transparent conductive film. Those skilled in the art willrecognize that additional optical coatings or functional coatings, suchas anti-reflective coatings and reflective or tinted coatings forcolor-matching, or barrier coatings such as those which preventmigration of moisture from the environment or sodium ions from the glassmay additionally be included above or below either of the top or bottomtransparent conductors.

At the end of the process, a last laser process makes the depicted P3cuts (through the top conductor but not the bottom conductor) and thedepicted P4 cuts (through both conductors) to finish isolating the filmsinto the desired zones. Bus bars are applied to the glass, followed byany additional process required (e.g., heating steps to fire the busbars or films). Lasers that are suitable for producing the cuts orablation lines include solid-state lasers, such as Nd:YAG at awavelength of 1064 nm, and excimer lasers, such as ArF and KrF excimerlasers respectively emitting at 248 nm and 193 nm. Other solid-state andexcimer lasers are also suitable.

Once deposition of the films comprising the EC stack/EC device and oncethe bus bars are deposited on the stack, the single pane of glass isfabricated into a laminate or insulated-glass unit. Methods of creatinga laminate comprising an EC device are disclosed in US PatentPublication No. 20110267672, the disclosure of which is herebyincorporated by reference herein in its entirety. As part of thisfabrication process, wires will be attached to the solder tab portion ofeach bus bar (see, for example, copending application U.S. Ser. No.61/490,291, the disclosure of which is incorporated by referenceherein).

Because the two (or more) electrochromic zones are not completelyindependent, but share a common bus bar, it is not possible to simplyconnect two channels of a standard electrochromic control system to theglass. A typical electrochromic control system will have a bridge-typeoutput, in which the output voltage is varied between +5V and −5V usingonly positive voltages, by varying which connection is at groundpotential. For example, applying ground (0V) to the negative wire and 3Vto the positive wire yields a positive 3V to an electrochromic pane, butreversing the two and applying 3V to the negative wire and ground (0V)to the positive wire yields −3V to the pane.

The solution for multi-zone EC devices having three zones is to add upthe required voltage for each pane and determine the correct potentialto apply to each wire (see, e.g., FIG. 4A). If one skilled in the artwere to apply 4V to the first wire, 2V on the second, and 0V on thethird, the result would be +2V on the first pane and −2V on the secondpane. In this way, the two panes can be completely independentlycontrolled. Generally, the control system must be capable of applying upto twice the voltage required of a single-zone controller, however.Similar logic applies to other multi-zone EC devices having more thantwo zones, such as four bus bar, three zone devices.

Another example is a 3-zone (4-busbar) device in which it is desired totint the first two panes at +3V, and clear the third at −2V. If thepolarity of the bus bars in sequence is +/−/+/−, we can apply 3V, 0V,3V, and 5V with respect to ground. The difference between the first twois 3−0=3; between the second and third is 3−0−3; and between the thirdand fourth is 3−5=−2. Note that for the purpose of driving theelectrochromic device, the absolute potential with respect to ground isless important, as opposed to the difference between potentials atadjacent bus bars. As such 4V, 1V, 4V and 6V, respectively, could havebeen applied to achieve the same result.

Current monitoring in each sub-pane is also believed to be morecomplicated in standard, single zone EC devices. In the 2-zone, 3-busbarcase, the two outside wires may be monitored to determine the current ineach sub-pane, whereas the middle wire carries the sum of the twocurrents. The 3-zone, 4-busbar case is more complicated yet. Here, thefirst wire carries the current of the first zone and the fourth wirecarries the current of the third zone (see, e.g., 4B). But to determinethe current flowing in the second (middle) zone, it is necessary tocalculate the difference in current between either the first and secondwires, or between the third and fourth wires.

Referring to FIG. 7, for this 2-pane, 3-busbar IGU, Pane 1 has anapplied voltage given by (V1−V2) and current I1, while Pane 2 hasapplied voltage of V3-V2 and current I3.

With reference to FIG. 8, for this 3-pane, 4-busbar IGU, Pane 1 stillhas applied voltage given by (V1−V2) and current I1. Pane 2 still canmeasure applied voltage as (V3−V2) but current is given by either(I2−I1) or (I4−I3). Pane 3 voltage is (V3−V4), with current (−I4).

Since multi-zone electrochromic devices have fully independent controlof each zone, it is possible for the zones to be different in size orshape. For example, and with reference to FIG. 2, while each of zones200A and 200B are depicted as having a generally rectangular shape, thesubject matter disclosed herein provides that a plurality of zones, eachhaving a selected shape, may be used. Further still, while multi-paneIGU 200 is depicted as having a generally rectangular shape, the subjectmatter disclosed herein provides that a multi-pane IGU of any selectedsize and shape can be used.

As a further non-limiting example, FIG. 5 shows a 4-busbar, 3-zonedevice in which the zones are different sizes (difference surfaceareas), and where one of the three zones is not rectangular in shape.For such devices, it is necessary to determine the appropriate voltageand current protocols to manage each individual sub-pane, and then thevoltage may be controlled and current monitored as described above inorder to manage each sub-pane with complete autonomy.

Because it is believed that the center bus bar(s) carry(ies) twice thecurrent of the edge bus bars, it is possible to reduce the thickness orwidth of the edge bus bars to achieve half the conductivity of thecenter bus bar. Alternatively, all bus bars may be made consistentlylarge enough to carry the full current.

In another aspect of the present invention, the electrochromic zones areformed from a single electrochromic coating on the substrate, whereinthe single electrochromic coating is cut to form individualelectrochromic zones. In some embodiments, the substrate comprises afirst bus bar and a second bus bar, wherein the first bus bar runscontinuously over each electrochromic zone. The second bus bar issegmented wherein each bus bar segment corresponds to an electrochromiczone. Each zone may be of a different size or shape, so long as it canbe designed in such a way that a single bus bar traverses all zonesalong one side.

The segmented second bus bar may formed from a single bus bar (appliedjust as the first bus bar is applied) and cut to form individual bus barsegments. In an alternate embodiment, the segmented second bus isapplied in segments or applied as a single bus bar that has one or moregaps.

Most of the processing (e.g. laser processing/cutting) is identical to anormal 2-busbar device. With reference to FIG. 6, however, there is anextra P4 cut which severs the films completely between the two operatingzones, preventing any current flow between them. In addition, one of thebus bars is segmented. Electrically, this unit works just like a3-busbar 2-zone device discussed previously, with one busbar connectedto the bottom conductor of both zones, and two separate busbarsconnected to the top conductor of each zone. The control hardware andlogic is identical to the 3-busbar case. Of course, the same logicapplies to devices having more than two zones. In some embodiments, thesubstrate is a laminate. In some embodiments, the electrochromic zonescomprise at least one thin film comprising a mixed tungsten-nickeloxide.

With reference to FIG. 9, for this 2-pane device having a segmented busbar, Pane 1 has an applied voltage given by (V1-V2) and current I1,while Pane 2 has applied voltage of V3-V2 and current I3.

In another embodiment, the P4 laser process described above is used tocut the films into three regions, with bus bar segments along each edgebridging the pairs of adjacent zones. This embodiment, it is believed,has the advantage of permitting all connections to be made near cornersinstead of along edges, which can allow at least some more space formaking connections. In addition, it is electrically comparable to the4-busbar, 3-zone device, with the three zones connected electrically inseries. In some embodiments, this permits fewer differentcontrols/wiring configurations than if one bus bar spans all zones, withthree separate segments on the opposite side.

In some embodiments, photochromic or thermochromic materials may be usedin place or in addition to the electrochromic materials disclosedherein. For example, some zones my comprise electrochromic materialswhile other zones may comprise at least one of an electrochromic,photochromic, or thermochromic material. Suitable photochromic materialsinclude, but are not limited to, triarylmethanes, stilbenes,azastilbenes, nitrones, fulgides, spriropyrans, naphthopyrans,sprio-oxazines, and quinones. Suitable thermochromic materials include,but are not limited to, liquid crystals and leuco dyes. Bothphotochromic and thermochromic materials can be formed on the substratein a well-known manner. No bus bars would be needed for photochromic orthermochromic dynamic zones because light and heat respectively modulatethe properties of the materials. One exemplary embodiment usingphotochromic and/or thermochromic dynamic zones could be a window havingat least one electrochromic dynamic zone towards the top of the windowthat is actively controlled for daylighting and at least onephotochromic dynamic zone towards the bottom of the window that selfdarkens when under direct light, and at least a second electrochromiczone posited in another region of the device.

Further, it should be understood that one exemplary embodiment of thesubject matter disclosed herein can comprise a window, such as anarchitectural window, having a single pane, or lite, that comprises aplurality of independently controlled dynamic zones. Another exemplaryembodiment of the subject matter disclosed herein comprises an IGUcomprising multiple zones of electrochromic window on one pane and clearglass on the other pane. Yet another exemplary embodiment of the subjectmatter disclosed herein comprises an IGU comprising multiple zones ofelectrochromic window on one pane and a low-E, tinted, or reflectiveglass on the other pane. Still another exemplary embodiment of thesubject matter disclosed herein comprises an IGU comprising multiplezones of electrochromic window on one pane of the IGU and a patterned orspecial glass on the other pane in which the patterning or features maymatch, compliment, and/or contrast the areas of dynamic zones on thefirst pane. It should be understood that the foregoing exemplaryembodiments can be configured so that the lite comprising the pluralityof dynamic zones is a clear lite, a low-E lite, a reflective, and/orpartially reflective lite.

Those of ordinary skill in the art will recognize that any of thecontrol, power, or wiring systems (including wireless control) describedin copending application U.S. Ser. No. 13/354,863 may be adapted for usewith a multi-zone electrochromic device as described herein.

Although the foregoing disclosed subject matter has been described insome detail for purposes of clarity of understanding, it will beapparent that certain changes and modifications may be practiced thatare within the scope of the appended claims. Accordingly, the presentembodiments are to be considered as illustrative and not restrictive,and the subject matter disclosed herein is not to be limited to thedetails given herein, but may be modified within the scope andequivalents of the appended claims.

What is claimed is:
 1. An electrochromic device comprising: a substratehaving a first side and a second side opposite the first side whereinthe substrate is a part of a window assembly; a first electrochromiczone having a first side and a second side opposite the first side,wherein the first side of the substrate is adjacent and closer to thefirst side of the first electrochromic zone than the second side of thefirst electrochromic zone, and the second side of the substrate isadjacent and closer to the second side of the first electrochromic zonethan the first side of the first electrochromic zone; a secondelectrochromic zone having a third side and a fourth side opposite thethird side, wherein the first side of the substrate is adjacent andcloser to the third side of the second electrochromic zone than thefourth side of the second electrochromic zone, and the second side ofthe substrate is adjacent and closer to the fourth side of the secondelectrochromic zone than the third side of the second electrochromiczone; a first bus bar having a length extending along the first side ofthe substrate, being adjacent to the first side of the firstelectrochromic zone and electrically connected to the firstelectrochromic zone and a first terminal, wherein the first bus bar isnot electrically connected to the second electrochromic zone; a secondbus bar having a length extending along the second side of thesubstrate, being adjacent to the second side of the first electrochromiczone and the fourth side of the second electrochromic zone andelectrically connected to the first and second electrochromic zones anda second terminal, wherein the second bus bar is a common bus bar forthe first and second electrochromic zones; and a third bus bar having alength extending along the first side of the substrate, being adjacentto the third side of the second electrochromic zone and electricallyconnected to the second electrochromic zone and a third terminal,wherein the third bus bar is not electrically connected to the firstelectrochromic zone, wherein the first and second electrochromic zonesare independently controllable, and the second side of the substrate iscloser to the second bus bar than to each of the first and third busbars.
 2. The electrochromic device of claim 1, wherein: the firstelectrochromic zone comprises a fifth side and a sixth side spaced apartfrom the fifth side, wherein each of the fifth and sixth sides isadjacent to the first and second sides of the first electrochromic zone,and no bus bar is electrically connected to the first electrochromiczone along the fifth or sixth side; and the second electrochromic zonecomprises a seventh side and an eighth side spaced apart from theseventh side, wherein each of the seventh and eighth sides is adjacentto the third and fourth sides of the second electrochromic zone, and nobus bar is electrically connected to the second electrochromic zonealong the seventh or eighth side.
 3. The electrochromic device of claim1, wherein the first bus bar is electrically connected to a first wirethat is electrically connected to a first voltage terminal, the secondbus bar is electrically connected to a second wire that is electricallyconnected to a second voltage terminal, and the third bus bar iselectrically connected to a third wire that is electrically connected toa third voltage terminal.
 4. The electrochromic device of claim 1,wherein the first and second electrochromic zones are in a coplanararrangement on a single substrate.
 5. The electrochromic device of claim1, wherein the substrate is transparent.
 6. The electrochromic device ofclaim 1, wherein the first bus bar, the second bus bar, and the thirdbus bar are permanently attached to the substrate.
 7. The electrochromicdevice of claim 6, where in the first bus bar, the second bus bar, andthe third bus bar are welded to the substrate.
 8. The electrochromicdevice of claim 1, wherein the substrate and the bus bars are a part ofa laminate.
 9. The electrochromic device of claim 1, wherein the firstbus bar has a different thickness than the second bus bar.
 10. Theelectrochromic device of claim 1, further comprising a second substrate,and wherein the second substrate is transparent.
 11. An electrochromicdevice comprising: a substrate having a first side and a second sideopposite the first side, wherein the substrate is part of a windowassembly, and wherein the substrate comprises: a first electrochromiczone; a second electrochromic zone; and a third electrochromic zone,wherein the second electrochromic zone is disposed between the first andthird electrochromic zones, wherein each of the first, second, and thirdelectrochromic zones has a first side adjacent to the first side of thesubstrate and a second side adjacent to the second side of thesubstrate, and wherein the first, second, and third electrochromic zonesare independently controllable; a first bus bar that is a first commonbus bar electrically connected to the first and second electrochromiczones along the first sides of the first and second electrochromiczones, wherein the first bus bar has a length extending along the firstside of the substrate and is not electrically connected to the thirdelectrochromic zone, and no electrochromic zone is disposed between thefirst bus bar and the first side of the substrate; and a second bus barthat is a second common bus bar electrically connected to the second andthe third electrochromic zones along the second sides of the second andthird electrochromic zones, wherein the second bus bar has a lengthextending along the second side of the substrate and is not electricallyconnected to the first electrochromic zone; and wherein the first busbar and the second bus bar do not overlie each other.
 12. Theelectrochromic device of claim 11, further comprising: a first wire anda first solder tab that electrically connects the first wire to thefirst bus bar; and a second wire and a second solder tab thatelectrically connects the second wire to the second bus bar.
 13. Theelectrochromic device of claim 11, further comprising a third bus barthat is electrically connected to the first electrochromic zone alongthe second side of the first electrochromic zone, wherein the firstelectrochromic zone is the only electrochromic zone on the substrateelectrically connected to the third bus bar.
 14. The electrochromicdevice of claim 13, further comprising a fourth bus bar that iselectrically connected to the third electrochromic zone along the firstside of the third electrochromic zone.
 15. The electrochromic device ofclaim 14, further comprising: a first wire and a first solder tab thatelectrically connects the first wire to the first bus bar; a second wireand a second solder tab that electrically connects the second wire tothe second bus bar; a third wire and a third solder tab thatelectrically connects the third wire to the third bus bar; and a fourthwire and a fourth solder tab that electrically connects the fourth wireto the fourth bus bar, wherein: the first bus bar is not electricallyconnected to the third electrochromic zone, the second bus bar is notelectrically connected to the first electrochromic zone, and the thirdelectrochromic zone is the only electrochromic zone on the substrateelectrically connected to the fourth bus bar; and the first, second, andthird electrochromic zones are in a coplanar arrangement on thesubstrate.
 16. The electrochromic device of claim 11, wherein the first,second, and third electrochromic zones are formed from a singleelectrochromic coating on the substrate.
 17. An insulated glazing unitcomprising the electrochromic device of claim
 11. 18. The electrochromicdevice of claim 11, wherein no electrochromic zone is disposed betweenthe second bus bar and the second side of the substrate.
 19. Theelectrochromic device of claim 11, wherein the first bus bar, the secondbus bar, and the third bus bar are permanently attached to thesubstrate.
 20. The electrochromic device of claim 11, wherein the firstbus bar has a different thickness than the second bus bar.